Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Goes well beyond the annotations (readOnlyHint=false, destructiveHint=false, openWorldHint=true) by disclosing partial-update semantics, that no notification reaches anyone, that the change is reversible by re-calling with the old value, that no confirmation prompt is issued, that approved documents retain their original details, and that a scoped API key is required. This is exactly the behavioral context an agent needs before mutating.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Action and scope are front-loaded, and each sentence carries real information (scope, notification, reversibility, approved-document edge case, auth). The phrasing is slightly roundabout in the reversibility sentence, but there is no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a mutation tool with no output schema, the description covers the side-effect profile, reversibility, notification behavior, an important edge case (approved documents), and auth requirements, so nothing essential for correct invocation is missing.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so both the field list and enum are already documented in the schema. The description restates the editable fields and adds the meaningful partial-update rule ('leaves the others as they are'), which is value beyond the schema, but it stops short of adding format or validation detail for tax_id/email.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a clear verb (Change) plus the resource (a contact) and enumerates the specific editable fields (name, type, email, tax ID). An agent can distinguish this from holded_create_contact, holded_get_contact, and holded_list_contacts without opening any schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description implies an update-existing-contact scenario and specifies the single-contact scope, but never explicitly names when to use it versus holded_create_contact or when not to call it. Usage is inferable but not stated.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.